And to reduce the fallout. 50mt vs 100mt came down to whether the jacket was U-238 or something inert. (U-238 can't do a chain reaction, but when subject to t

And to reduce the fallout. 50mt vs 100mt came down to whether the jacket was U-238 or something inert. (U-238 can't do a chain reaction, but when subject to the neutron flux of an h-bomb it's willing to fission and increase the yield.)